I. Field of the Invention
The present invention relates to a process for treatment of anthracite coal.
More particularly it relates to magnetic separation of previously processed anthracite coal from klinker type ash or cinders, which is an industrial waste product of pre 1960, anthracite treatment centers or coal breakers.
II. The Prior Art
Anthracite coal which is found predominantly in Northeastern Pennsylvania is unique among coals in that it has a very high fixed, non-volatile carbon content. As a result, this coal does not lose an excessive quantity of its combustion value upon standing in ambient air conditions. It remains stable for long periods of time, perhaps centuries. This is not true of Bituminous and Lignite coal found elsewhere in the world.
Further, each coal type, depending on its properties, caused development of distinct methods of production, liquification and reclamation.
In the early production of anthracite, coal removed from the mine was transported to coal breakers where it was crushed, cleaned, sized and washed.
During this time frame, that is the 19th and early to mid 20th centuries, only the larger sizes where considered commercially valuable. These sizes were designated "pea" or "chestnut" coal.
Smaller coal pieces or chips and washings were considered waste and were consequently discarded. Today these products are valuable due to the use of improved coal fired boilers, stokers which use smaller sized coal as well as steam generators for electric plants and gasification units being developed in the overall synthetic fuel advances being made throughout the world. Yet these previous considered waste products are generally not found alone and separated, but rather mixed with other waste or undesirable materials.
During this same time frame, the coal treatment plants or breakers, were fired by the most available and cheapest fuel-anthracite coal. The energy derived from burning anthracite produced the power to operate the entire processing plant. As a result, a second waste product was produced, boiler ash; a klinker-type ash. This was discarded in the same waste areas as the waste chips of anthracite previously discussed.
Many times, the mixture was simply piled into great heaps which now dot the landscape of the anthracite region. Other times, it was used to make beds for railroads. Much was washed into streams and rivers creating large silt washes. The coal in this mixture retains a high combusition rating and when mixed with refined coals, usually anthracite, is used to power industrial processes.
An economical method is needed which would increase the combustion value of the waste anthracite-klinker type cinder mixture. This could best be accomplished by removal of the cinders from the previously mentioned mixture thereby permitting the recovered anthracite to be used as a primary fuel.
A method is needed to create economic feasibility to renewal and use of the unsightly heaps and silt washes which dot the landscape of anthracite regions such as Northeastern Pennsylvania.
The present invention provides such a method and solves these problems long prevalent in the field of anthracite technology.
Processes presently patented for improving coal quality can best be characterized by U.S. Pat. No. 3,938,966 and U.S. Pat. No. 4,120,665 both issued to James K. Kindig. The primary focus of these patents is to remove pyrite, i.e. the major inorganic sulfur-containing component from bituminous coal. They are not designed to remove preformed, existing ash or cinders from a mixture such as the previously mentioned waste.
Further, these processes require pretreatment and preheating of the coal to be operable which is not feasible when dealing with preprocessed coal. Further, these patents although they use magnetics generally, treat raw coal with metal containing compounds to enchance the magnetic susceptibility of the contaminates for magnetic removal.
None of these steps is utilized in the present invention.